In the prior art, in general, an optical information recording and reproduction device comprises a disc rotation mechanism to drive rotation of an optical disc at a prescribed speed; an objective lens driving device, having an objective lens which condenses a light beam on the information recording portion of the optical disc; a slide base on which the objective lens driving device is mounted; and a pickup movement device which moves the slide base along the information recording portion of the optical disc.
As conventional objective lens driving devices used in such optical information recording and reproduction devices, for example, devices such as that described in Japanese Patent Laid-open No. 63-177323 are known. This conventional objective lens driving device has a magnetic circuit portion having a magnet and yoke, and an electromagnetic coil; the electromagnetic coil is positioned within the magnetic flux generated by the magnetic circuit portion. By passing a current through this electromagnetic coil, an electromagnetic force is generated due to the magnetic force of the magnet. By fixing either the electromagnetic coil or the magnetic circuit portion to the objective lens assembly, the objective lens can be driven.
FIG. 22 is used as FIG. 1 in the above-mentioned Japanese Patent Laid-open No. 63-177323, and is a drawing showing the yoke and frame used in the objective lens driving device. In FIG. 22, symbol 1 denotes a frame formed from magnetic material. The frame 1 comprises a plate in which is provided an aperture 2 in the substantial center; at two locations corresponding to peripheral edges of this aperture 2 are provided, by raising upward the inner-edge portions, inside yokes 3a, 3b. Outer yokes 4a, 4b are provided, by raising upward the outer-edge portions of the frame at two locations, so as to oppose the inside yokes 3a, 3b. 
Magnets 5a, 5b are provided integrally, bonded using adhesive to the faces of these outer yokes 4a, 4b facing the inner yokes 3a, 3b. A gap of prescribed size is provided between each of the magnets 5a, 5b and the inside yokes 3a, 3b. In these gaps are inserted a portion of a pair of coil members installed on a moveable member supporting the objective lens, not shown, such that the magnets 5a, 5b do not make contact with the respective inside yokes 3a, 3b. 
The pair of coil members comprises a pair of focusing coils mounted so as to surround the inside yokes 3a, 3b, and a tracking coil fixed on the sides of the magnets 5a, 5b of the focusing coils. The pair of coil members are mounted on the moveable member, and the moveable member is movably supported by the frame 1 via a support mechanism. A pair of support pins 6a, 6b are provided in the frame 1 to support the support mechanism.
However, in a conventional objective lens driving device such as this, a pair of inside and outside yokes 3a, 3b and 4a, 4b are provided in opposition on the frame 1 of magnetic material, and magnets 5a, 5b are fixed and supported by the outside yokes 4a, 4b, while at the same time, coil members are mounted so as to surround the inside yokes 3a, 3b in opposition to the magnets 5a, 5b, so that the following problem arises.
That is, because a pair of inside and outside yokes 3a, 3b and 4a, 4b is required on the frame 1, the construction of the frame 1 is complex and machining properties are poor. Moreover, because the positioning of the inside yokes 3a, 3b and outside yokes 4a, 4b must be performed with high precision, assembly is difficult, and results in increased costs.